Biology subjects

Torok, A.

Publications and source records attributed to Torok, A..

3 recordsLinked to original sources

bioRxiv2018

Looking at the map -- or navigating in a virtual city. Interaction of visuospatial display and spatial strategies in VR

To study geo-visualization processes a Cognitive Cartography Lab was established at Eotvos University, and the \"Virtual Tourist\" experiment was designed for the better understanding of actual map use during navigation. In this paper we present some preliminary results of the experiment. We explored the use of a static, north-oriented city map during navigation in an interactive, 3D town. Participants explored the virtual environment or followed verbal instructions before they completed spatial tasks. Their spatial behavior, verbal reactions were recorded, and also eye tracking data from 64 participants was collected. The experiment was designed by a multidisciplinary research group, including students of Eotvos Lorand University.

neuroscience↗

bioRxiv2018

A novel virtual plus-maze for studying electrophysiological correlates of spatial reorientation

Quick reorientation is an essential part of successful navigation. Despite growing attention to this ability, little is known about how reorientation happens in humans. To this aim, we recorded EEG from 34 participants. Participants were navigating a simple virtual reality plus-maze where at the beginning of each trial they were randomly teleported to either the North or the South alley. Results show that the teleportation event caused a quick reorientation effect over occipito-parietal areas as early as 100 msec; meaning that despite the known stochastic nature of the teleportation, participants built up expectations for their place of arrival. This result has important consequences for the optimal design of Virtual reality locomotion.

neuroscience↗

bioRxiv2018

Phase of neuronal activity encodes 2-dimensional space in the human entorhinal cortex

The entorhinal cortex plays a vital role in our spatial awareness. Much focus has been placed on the spatial activity of its individual neurons, which fire in a grid-like pattern across an environment1. On a population level, however, neurons in the entorhinal cortex also display coherent rhythmic activity known as local field potential. These local field oscillations have been shown to correlate with behavioural states but it remains unclear how these oscillations relate to spatial behaviour and the spatial firing pattern of individual neurons. To investigate this, we recorded entorhinal cortical neurons in the human brain during spatial memory tasks performed in virtual environments. We observed a spatial modulation of the phase of action potentials relative to the local field potentials. In addition, the spike phase modulation displayed correlation with the movement of the avatar, displayed discrete phase tuning at the cellular level, rotated phase between electrodes, and expressed spatially coherent phase maps that scaled with the virtual environment. Using surrogate data, we demonstrated that spike phase coherence is dependent on the spatial phase dynamics of gamma oscillations. We argue that the spatial coordination of spike generation with gamma rhythm underlies the emergence of grid cell activity in the entorhinal cortex. These results shed a new light on the intricate interlacing between the spiking activity of neurons and local field oscillations in the brain.

neuroscience↗